scholarly journals Exergy and Exergoenvironmental Assessment and Optimization of Low GWP Refrigerant for Vapor Compression Heat Pump System

2018 ◽  
Vol 9 (6) ◽  
pp. 1256
Author(s):  
Nyayu Aisyah ◽  
Muhammad Idrus Alhamid ◽  
Nasruddin Nasruddin
Keyword(s):  
Heat Pump ◽  
Vapor Compression ◽  
Pump System ◽  
Heat Pump System

scholarly journals The Analysis of Vapor Compression Heat Pump System for Rough Rice Drying

2016 ◽  
Vol 04 (2) ◽  
pp. 1-8
Author(s):  
Damawidjaya Biksono ◽  
◽  
Leopold Nelwan ◽  
Tineke Mandang ◽  
Dyah Wulandani ◽  
...  
Keyword(s):  
Heat Pump ◽  
Vapor Compression ◽  
Pump System ◽  
Heat Pump System ◽  
Rough Rice ◽  
Rice Drying

scholarly journals Exergy Evaluation of a Heat Supply System with Vapor Compression Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1028 ◽  
Author(s):  
Agata Rijs ◽  
Tomasz Mróz
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Heat Supply System ◽  
Heat Pumps ◽  
Supply System ◽  
Exergy Efficiency ◽  
Vapor Compression ◽  
Outdoor Temperature ◽  
Pump System ◽  
Heat Pump System

The vapor compression heat pumps are very popular solutions regarding heat supply systems of modern, low energy buildings. It is partly due to the fact that they are treated as a sustainable heat supply. The question arises: Can a vapor compression heat pump be treated as a sustainable heat supply? To answer this question; the exergy model of a heat pump system operation has been proposed. The proposed model has been employed for evaluation of exergy efficiency of an existing heat supply system equipped with two heat pumps installed in an educational building located on the campus of Poznan University of Technology, Poznan, Poland. The analysis shows that the system exergy efficiency decreases with an increase in outdoor temperature and its values are in the range of 10.9% to 42.0%. The primary exergy efficiency, which considers the conversion of fossil fuel into electricity, is on average 3.2 times lower than the system exergy efficiency for the outdoor temperature range of −9 °C to 11 °C. The performed analysis allowed for the identification of a set of solutions that may increase the exergy and primary exergy efficiency of the system. The first solution is to cover a part of the electricity demand by a renewable energy source. The second proposition is to apply a low-temperature emission system for heating. The third idea is to apply a district heating network as the heat supply instead of the heat pump. The conclusion is that the exergy performance of systems with heat pumps is rather poor because they generate low-quality heat from high-quality electricity. The best way to improve the primary exergy efficiency of a heat pump system is to power the system by electricity generated from a renewable energy source.

Theoretical and Experimental Study on the Falling-Film Evaporator Applied to Mechanical Vapor Compression

2013 ◽  
Vol 753-755 ◽  
pp. 2667-2673 ◽  
Author(s):  
Wei Ke Pang ◽  
Lu Wei Yang ◽  
Zhen Tao Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
High Efficiency ◽  
Film Flow ◽  
Falling Film ◽  
Vapor Compression ◽  
Pump System ◽  
Heat Pump System ◽  
Film Evaporator ◽  
Heat Transfer Efficiency

Based on a heat pump system of mechanical vapor recompression (MVR) designed and manufactured independently, the heat transfer performance of falling-film evaporator was measured by a combination way of theory analysis and experiment proving as the heat pump operated in practice. After the result of theoretical calculation is worked out, the start thickness and entrance velocity of the liquid film are established by adjusting the flux of raw solution. The result shows there is an optimization that the film thickness at the bottom of the tubes amounts to that of boundary layer of velocity. Additionally, it is a process of falling-film flow with heat and mass transfer between the start and end of falling-film. The last thickness of the falling film is about 0.21~0.44mm. The thickness of falling film when the falling-film flowed and heat exchange was over is compared with each other, and the effect of heat resistance on heat transfer is discussed also. It is showed that an optimal thickness is formed during the process of falling-film flow and evaporation, and disadvantages come up when it is not formed. The falling-film evaporator propelled by the MVR heat pump with low compression ratio carries through a process of strong and high-efficiency heat transfer with phase transition. It is because the states of produced vapor both before compressed and after compressed are saturated. Its heat-transfer coefficient may be as high as 1990 W/ (m2·K). The start and end thickness of falling film become great while the evaporation pressure goes up. It leads to the drop of the heat-transfer efficiency, so there is an optimization to the system in all probability.

Simulation of Miniature Vapor Compression Heat Pump System

2011 ◽  
Vol 291-294 ◽  
pp. 3126-3130
Author(s):  
Xiao Hui Zhong ◽  
Yu Jun Gou ◽  
Shu Guang Zhou ◽  
Zhi Mei Wen
Keyword(s):  
Steady State ◽  
Heat Pump ◽  
Relative Error ◽  
State Model ◽  
Simulation Program ◽  
Vapor Compression ◽  
Pump System ◽  
Heat Pump System ◽  
Optimal Match ◽  
Steady State Model

A prototype of miniature vapor compression heat pump system was introduced. On the basis of compressor, capillary, condenser and evaporator models, the steady-state model of air-to-water miniature heat pump system is developed with regard to energy and refrigerant inventory conservations among all these components. The results show that the relative error between prediction and experiment values is less than 5%, and the optimal match of condenser and evaporator lengths were obtained by simulation program.

3 kW Class Displacer Type Stirling Engine for Heat Pump System

1987 ◽  
Author(s):  
T. Nomaguchi ◽  
T. Suganami ◽  
M. Fujiwara ◽  
M. Sakai ◽  
T. Koda ◽  
...  
Keyword(s):  
Heat Pump ◽  
Stirling Engine ◽  
Pump System ◽  
Heat Pump System
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